Self-cleaning high lift bucket



April 15, 1969 A. BAKER 3,438,526

SELF-CLEANING HIGH LIFT BUCKET Filed Feb. 1967 Sheet of 2 l NVEN TOR. A area-o Bnxse C'Afib msxsOI/eo macs H15 ATTGRNEYS April 15, 1969 A. BAKER SELF-CLEANING HIGH LIFT BUCKET Sheet Filed Feb. 7, 1967 VENTOR. A1. FRED BAKER BY CAROTHEK$CAOTHE5 H/sAr-rozusxs United States Patent 3,438,526 SELF-CLEANING HIGH LIFT BUCKET Alfred Baker, 28 Sharp Ave., Washington, Pa. 15301 Filed Feb. 7, 1967, Ser. No. 614,505

Int. Cl. E02f 3/70; 1360p 1/06 US. Cl. 214767 Claims ABSTRACT OF THE DISCLOSURE A bucket cleaning scraper blade for a high lift excavator, in which the scraper blade drive lever is spring biased for movement in opposite directions to prevent breakage of the interconnecting parts of the scraper blade drive connections when the blade is blocked against movement in either direction by a load in the bucket.

Related cross-references This invention is an improvement on my Patent 2,683,542 for Self-Cleaning High Lift Bucket which issued July 13, 1954.

Object of invention The principal object of this invention is the provision of a scraper blade drive including a lever having opposed biasing springs providing free movement of the scraper blade drive lever in one direction when the scraper blade is blocked against movement by a load in the bucket when the latter is back racked.

Background of the invention A high lift excavator has a tiltable bucket pivotably supported on an independently controlled pair of lift and dump arms actuated from a self-propelled tractor body. The dump arm, formerly made as one member, is now made in two sections connected by a multiplying lever to aid in tilting the bucket upwardly as it is raised upwardly through the material being handled, which in the art is referred to as back rack. This back rack action will fully load the bucket. When the bucket is at the intended height the dump arm is actuated to pivot the bucket forwardly on the lift arm and dump the contents.

When digging congealed dirt, gumbo'or snow the load sticks to the bucket. The self-cleaning bucket of the prior art has a U-shaped scraper blade that is driven by the tilting action of the bucket when a light chain walks around a sprocket, secured to a drive lever, to drive the blade and scrape out the bucket.

When the load in the bucket blocks the movement of the scraper blade a light chain in the scraper blade drive breaks.

To avoid this a biasing spring on the lever was used to absorb this blocking force by permitting the lever and its sprocket to move with the tilting bucket as shown in 2,683,542.

Summary of the invention When this scraper blade lever drive is employed in a bucket that has back rack action the chain breaks with my known structure because of the tilting action on the bucket, or back rack, attempts to move the scraper as the load is being shoveled into the bucket by this upward sweeping and tilting movement, namely, back rack. The scraper blade is held by the load before it rises at the uppermost position.

The object of this invention is to prevent the chain and other parts of the scraper blade drive from breaking on this back rack or back tilting of the bucket. To merely bias the movement of the scraper blade drive lever is impossible because the biasing load is sufficient to break the chain. The space is limited.

An important object of this invention is to free the scraper blade drive lever from movement relative to the bucket when the latter is back racked when carrying a load and when the scraper blade is blocked. The next object is to recapture this drive lever when the bucket is tilted in the opposite or dumping direction and place it under spring biased pressure suflicient to move or return the scraper blade when blocking load is removed to clean the bucket.

Another object is to provide support for the member, to which the biasing springs are secured, when this member is uncoupled or unseated from drive lever means, to allow the latter to move with the bucket and release pressure on the chain to the scraper blade when blocked by a load and also to restore the member on the seat of the drive lever when the bucket is returned. When the drive lever is drawn rearwardly, the member is unseated and it is supported entirely by the springs alone or the springs with the stop. These are important features of this invention.

Brief description of dralwings Other objects and advantages appear hereinafter in the following description and claims.

The accompanying drawings show, for the purpose of exemplification without limiting the invention or the claims thereto, certain practical embodiments illustrating the principles of this invention wherein:

FIG. 1 is view in side elevation of a high lift indicating several positions of the bucket.

FIG. 2 is an enlarged sectional view showing the bucket with the scraping blade driving lever, and biasing springs.

FIG. 3 is sectional view similar to FIG. 2 showing the bucket back racked and drive chain with take up for the scraper blade.

FIG. 4 is a transverse sectional View showing the rear of the bucket.

FIG. 5 is an enlarged detailed view of the scraper blade drive lever and biasing springs. 7

FIG. 6 is an enlarged detailed view showing a radius support as a modification of the back rack biasing spring comprising this invention.

FIG. 7 is an enlarged detailed view of another modified form of the scraper blade lever drive means with opposed biased springs connected in tension through a lever.

FIG. 8 is an enlarged detailed view of another modified form of the scraper blade lever drive means with opposed biased springs connected in tension and compression.

The high lift excavator of FIG. 1 includes a mobile power unit 1 on spaced independently operated endless tracks 2 to carry the spaced lift arms 3 pivotally supported on each side of the unit. These lift arms are power actuated by the double acting fluid power cylinders pivoted to the power unit 1. The piston rods 7 extending from the cylinders are pivoted at 8 on the depending knee of these lift levers 3 for the purpose of raising and lowering the bucket 10. The pivot members 11 hingedly attaching the bottom of the bucket 10 to the ends of the lift levers 3.

The bucket dump arms 12 are constructed in two lengths 13 and 14 with their adjacent ends interconnected to the multiplying lever 15 at their respective pivot points 16 and 17. The multiplying lever 15 is in turn pivotally supported on the lift arms 3 as shown at 18.

The inner dump arms 13 may include double acting fluid dumping cylinders and are each pivoted to one end of their respective arms which are in turn pivotally supported on the unit 1. The end of the arms pivotally carry one end of the double acting dumping cylinders and the pistons therein are slidable in their operating cylinders. The opposite ends of the pistons may be pivoted at 16 to the multiplying lever 15.

The outer dump arms 14 are pivoted to the bucket 10 as indicated at 27.

This high lift excavating structure is well known in the market and the arrangement of the lift arms 3 and the dump arms 4 provide a partial back rack of the bucket 10 as it is moved into the material to be dug or lifted. A complete back rack to place the bucket 10 in its highest position, and when holding water the surface of which would be horizontal, requires some back pull on the dump arms by the dump cylinders as the bucket is being hoisted in this position. Generally speaking the dumping arm arrangement shown is factual and performs to some degree back rack of the bucket on its upward di ging swing. The operator must do the rest.

The bucket 10 and its scraper mechanism is similar to that shown in Patent 2,683,542. As shown in FIGS. 2 and 3 the bucket 10 is provided with the U-shaped scraper blade which with its side arms 31 is shaped to lit the smooth interior wall surface of the bucket 10. The arms 31 are secured to the stub shafts 32 that extend through bearings in the bucket side walls and have their respective sprockets 33 secured thereto. The chains 34 extend around their respective sprockets 33 and 35 and removable take-up 36 is provided in each chain enclosure 37. The sprockets 35 are secured to their respective stub shafts 38 preferably journaled on the same axes as that of the dump arm axes 27. The stub shafts 38 are journaled on the back of the bucket and have the upwardly extending drive levers 40 secured thereto. These levers are secured relative to the stub shafts 38 and the chains 34 and sprockets 33 and 35 are all positioned to place the scraper blade 30 near the top of the bucket in FIG. 3 when the drive levers 40 are forward and are preferably closely spaced from the back of the bucket. When the empty bucket is tilted back and forth on the pivots 11 the chains 34 walk around the sprockets 35, which are stationary relative to the bucket 10, and cause the scraper "blade 30 to move from one extremity to the other as shown in dotted lines in FIG. 1 with the bucket in its raised position and is similar to that shown in the above mentioned patent.

The scraper drive levers 40 are provided with a seat 41 which faces forwardly having a horizontal face 42 and a vertical face 43. This seat could be merely an arcuate indentation on the forward face of the drive lever 40. This seat 41 aligned on each lever is for the purpose of receiving the member 44 which is preferably a rod or bar longer than the distance between the two drive levers 40 so that it may be supported on the seat 41 of each scraper drive lever 40.

A pair of anchor lugs 45 and 46 are pivotally mounted beside each other adjacent each end of said member 44. Each lug 45 is secured to one end of the biasing spring 47 the other ends of which are secured to the forward dumping arms 14.

Each lug 46 is secured to one end of the downwardly depending back rack scraper blade opposed biasing spring 48 comprising this invention the other end of which is secured at 49 to its respective drive lever arm 40.

When the bucket 10 is being raised while loading which load binds and blocks movement of the scraper blade 30, the back rack action of the lift and dump arms on the bucket, causing it to tilt back as the bucket rises, forcing the scraper drive levers 40 rearwardly from the bucket withdrawing the seat 41 on each drive lever from the rod member 44 and places a biasing tension on the springs 48 and prevents the drive chains and sprockets from breaking and allows the member 44 to press against the spaced stops 50 on the dump arms 14. The arrested scraper blade forces the lever 40 rearwardly and expands springs 48 placing an opposed biasing pressure on the levers 40. These stops have a front shoe 51 which receives the rubbing action of the member 44 as the springs 48 expand under tension. If and when the binding load on the scraper blade 30 is released as by dumping the load or a portion thereof, the biasing springs 48 pull the scraper driving levers 40 toward the member 44 causing the scraper blade 30 to move to the top of the bucket where it normally would have gone if it had not been blocked by the load.

Further forward movement of the scraper driving levers 40 seats the member 44 on the seats 41 and this tilting action to dump the bucket 10 causes the scraper driving levers 40 to force the scraper blade 30 to move in the opposite direction. If the scraper blade meets with resistance to move it because of a blocking load the drive levers 40 are held fast by the biasing spring 47 and the bucket moves forward to dump. This provides a relative movement of the bucket 10 and the scraper drive levers 40 permitting the scraping blade to remain relatively stationary as the chain 34 does not walk around the sprocket 35 but the latter moves with the scraper drive levers 40 to prevent this action but the biasing springs 47 stretch.

This forward action continues until the biasing spring 47 load excels that of the dirt blocking load permitting the scraper drive lever 40 to move forward to that position where the scraper drive levers 40 remain at rest relative to the bucket and any continued dumping action of the bucket 10 on the pivots 11 cause the spring 47 to rotate the sprockets 35 and the chain 34 continues to move the scraper 30 to scrape the interior of the bucket to the end of the dumping stroke in proportion to the diminishing load on the spring 47.

Thus the back rack biasing spring 48 serves to return the scraper drive lever 40 in position to receive the member 44 on the lever seat 41 and permit the scraper blade 30 to continue scraping the bucket until it reaches the bot tom of the bucket as it is shown in the fully dumped position in FIG. 1.

In the modified structure shown in FIG. 6 an arcuate depression 52 in the front face of the scraper drive levers 40 forming the seat on which the rod member 44 comes to rest. The radius rod 53 freely supported on the pivot 38 and on the member 44 supports the latter. The member 44 is arrested by the stop 50 as it leaves the seat 52 when scraper drive lever 40 moves rearwardly placing tension on the biasing spring 54. Since the radius rod 53 supports the member 44 any suitable tension spring may be employed as the back rack biasing spring to bring the scraper drive lever 40 back to its seat on the rod member 44 when the load on the scraper blade has been sufficiently relieved to permit the spring 54 to move the scraper blade and avoid breaking the chain and sprocket drive. This spring is shown as a coil spring 54 secured between the drive lever 40 and the member 44 or the radius rod 53. The spring 54 could be a resilient elastomer member such as a stretchable belt or a band formed from a pneumatic inner tube or the like.

Referring to the next modification shown in FIG. 7 the lever scraper drive means 40 is connected directly through the member 44 to one end of the spring 47. ,As in my previous disclosure when the bucket 10 is dumped and the scraper blade 30 is blocked by a load in the bucket and the lever 14 moves forwardly with the bucket hinged on 11 and the spring 47 stretches until the blocking load force that prevents breakage of the sprocket and chains and is sufl'iciently light to allow the scraper to move and the spring draws the lever 40 back to drive the scraper blade to the bottom of the bucket to clean the same which function is the same as described in regard to FIGS. 1 to 4.

When the bucket is returned to the horizontal position shown in FIGS. 1 and 2 the spring 47 collapses and becomes a solid member which in FIG. 7 will force the lever 55 causing it to pivot at 56 and expand the opposed biasing spring 57 when the back rack action of the bucket as shown in FIG. 3 is made while loading which load blocks the movement of the scraper blade 30. Thus the spring 57 is an opposed biasing spring that functions in the same manner as springs 48 and 54. This is just another modification of the biasing springs and in view of the fact that they function in back of the lever drive means the stop is not employed. If there is no load during the back rack action the scraper 30 of FIG. 7 merely swings upward in the bucket and there is no expansion of the spring 57.

In the modified structure of FIG. 8 the Springs 47 and 58 are opposed to each other and function to compress spring 48 rather than expand spring 57 as in FIG. 7. Springs 47 and 58 have their adjacent ends secured to the movable block 60. When spring 47 is fully collapsed as shown it functions as a solid member as in FIG. 7 to push on the movable block 60 to compress the spring 58 between the block 60 and the stop -61 on the front section 14 of the dump arms 12. Thus the compression of the spring 58 prevents the chain and sprocket from breaking and functions as a bias on the scraper blade 30 and the energy stored in the compressed spring 58 is utilized to move the scraper blade when the blocking load is relieved to a pressure less than the applying pressure of this spring. If there is no load on the scraper blade 30 in FIG. 8 the blade merely swings upward in the bucket and there is no compression of the spring 58. It will be noted that in the modification the stop 50 is eliminated.

Thus the reverse biasing spring 57 for back rack may be under tension by the use of the lever or under compression if attached to the lever 55 above the pivot or if attached to the slid block as shown in FIG. 8.

In FIGURES l to 5 the fixed end of said reverse biasing spring 48 is secured to the lug 49 which in turn is fixed to the scraper drive levers 40. In FIG. 6 the fixed end of the reverse biasing spring 54 is likewise fixed to the same scraper drive lever. These scraper drive levers 40 are fixed to the rotary shaft 38, which is coaxial with shaft 27, and both are pivoted to the bucket, which in turn is carried on the shaft 27 by the end of the parallel dump arms 14.

This common axis of the shafts 38 and 27 thus provide a fixed dimension support means between the end of the reverse biasing springs 48 and 54 and the dump arms 14, as defined in the claims.

Since the dimension of the support means from the dump arms 14 to the spring ends 48 and 54 cannot change by the swinging movement of the scraper drive levers 40 and these scraper drive levers 40 are actually supported from the dump arms 14, and since the lugs 61 of FIGS. 7 and 8 also indirectly support the ends of the reverse biasing springs 57 and 58.

Therefore, a fixed dimensional support means is provided from the dump levers 14 to support one end of each of the reverse biasing springs 48, 54, 57 and 58.

I claim:

1. A high lift excavator including a mobile power unit carrying power operated lift and dump arms to actuate a bucket supported on pivotal axes on the ends of said arms, scraper lever drive means pivoted on said bucket and connected to actuate a scraper blade pivoted on and to rotate and scrape the inside of said bucket when dumped, a dumping spring connected to bias said scraper lever drive means, characterized by a second and reverse biasing spring connected to operate said scraper lever drive means in a direction opposite to said first biasing spring when said bucket is pivoted to back rack and said blade is blocked by a load, a fixed dimension support means from said dump arms indirectly connected to one end of said reverse biasing spring, and said other end of said reverse biasing spring connected indirectly to one end of said dumping spring.

2. The high lift excavator of claim 1 characterized by a stop mounted on said dump arms and provided with a face for engagement to control said lever drive means during back rack action of said bucket.

3. The high lift excavator of claim 2 characterized in that said lift and dump arms and said lever drive means are in duplicate being spaced from each other on aligned axes adjacent the opposite sides of said bucket.

4. The high lift excavator of claim 3 wherein said lever drive means including a rod extending to be engaged by seating on both of said lever means and to engage with said stop.

5. The high lift excavator of claim 1 characterized by a movable support secured between the adjacent ends of said first spring and said second spring and reverse biasing spring the other end of said second spring which is secured to said durn-p arm to compress the latter when the former is fully collapsed as a solid member permitting said lever drive means to move back as said bucket is pivoted to back rack and said scraper blade is blocked by aload.

6. The high lift excavator of claim 1 characterized by a lever pivoted on said dump arm with its opposite ends secured between said first and said second and reverse biasing spring to expand the latter when the former is fully collapsed as a solid member permitting said lever drive means to move back as said bucket is pivoted to back rack and said scraper blade is blocked by a load.

7. The high lift excavator of claim 2 characterized by a forwardly open seat on said lever drive means, a member secured to the free end of said first biasing spring and arranged to be positioned and retracted relative to said seat and engage said stop, said second and reverse biasing spring connected to operate between said drive lever means and said member.

8. The high lift excavator of claim 6 characterized by a connecting means between one end of said reverse biasing spring and said member, and a second connecting means between the other end of said reverse biasing spring and said lever drive means adjacent its pivotal axis.

9. The high lift excavator of claim 6 characterized by a radius rod between the axis of said lever drive means, said reverse biasing spring connected between said lever drive means and said radius rod.

10. The high lift excavator of claim 1 characterized by a forwardly open seat on said lever drive means, a member movable to rest on and move relative from said seat and secured to the free ends of said first and said second and reverse biasing spring the other end of the latter of which is secured to said lever drive means near to its plvotal axis to stretch said reverse biasing spring when said lever drive means is retracted from said member and moved back as said bucket is pivoted to back rack and said scraper blade is blocked by a load.

11. The high lift excavator of claim 1 characterized by a forwardly open seat on said lever drive means, a member movable to rest on and move relative from said seat and secured to the free ends of said first biasing spring, a radius rod supporting said member from the 'axis of said lever drive means to permit said member to =reseat on said seat, said reverse biasing spring connected between said lever drive means and said radius arms.

12. The high lift excavator of claim 7 wherein said second and reverse biasing spring is a stiff coil spring that retains the height of said member when it is approached by said seat on said lever drive means.

'13. The high lift excavator of claim 1 characterized by a radius rod supporting said member from the pivot of said lever drive means, and said second spring is connected between said radius rod and said lever drive means.

14. The high lif-t excavator of claim 13 wherein said second spring is a coil spring.

15. The high lift excavator of claim 13 wherein said second spring is an elastomer.

References Cited UNITED STATES PATENTS 2,683,542 7/ 1954 Baker. 2,858,035 10/1958 Met-tetal 214-510 H'UGO O. SCHULZ, Primary Examiner.

US. Cl. X.R. 2145 10 

